2 Best Sights in Aspen and the Roaring Fork Valley, Colorado

Glenwood Springs is home to the Historic Fairy Caves (now part of the adventure park), whose subterranean caverns, grottoes, and labyrinths are truly a marvel of nature—the area was touted as the "Eighth Wonder of the World" when it opened to the public in the 1890s. The still-amazing caves are easily accessible year-round via the Glenwood Gondola, which offers a bird's-eye view of downtown, the Colorado River, and surrounding mountains. Choose from two different 40-minute walking tours of the caves, or opt for the crawl-on-your-belly "Wild Tour" spelunking adventure. For a second helping of adrenaline, try the gravity-powered alpine coaster that winds down 3,400 feet down the mountain; sail out over 1,300 feet above Glenwood Canyon on a giant swing; or drop, roll, and twist on the Defiance roller coaster that overhangs a cliff.

Part of the Yampah Spa and Salon, the hot springs vapor caves are a series of three underground, geothermal steam baths. Mineral-filled water from a natural hot spring runs about 125°F under the floors of one of the few known natural vapor caves in North America, creating steam temperatures of 110°F–112°F within the rock chambers, where there are marble benches for you to sit on while you inhale the steam. You can take a break in an adjacent cooling room or the upstairs solarium when you need it. Spa treatments are also available, including massages, body wraps, and private mineral baths. Reservations are required and visitors are limited to two hours.